docs: def _handle_event(self, connection, event):
          """
          Handle an Event event incoming on ServerConnection connection.
          """
          with self.mutex:
              matching_handlers = sorted(
                  self.handlers.get("all_events", [])
                  + self.handlers.get(event.type, [])
              )
              for handler in matching_handlers:
                  result = handler.callback(connection, event)
                  if result == "NO MORE":
                      return